1. Field of the Invention
The present invention relates to an image forming apparatus for forming an image on a record medium such as a photosensitive member.
2. Related background art
FIG. 4 is a schematic view for explaining the operation of laser beam exposure according to the prior art, wherein a photosensitive drum 51 is rotated in a direction of arrow a with an drive means (not shown). Reference numerals 52 and 53 represent laser beams which are scanned for exposure in a direction of arrow b. The photosensitive drum 51 is controlled to rotate constantly at constant speed with the drive means upon reception of a copy start command.
In forming a latent image on the surface of the photosensitive drum 51, a laser beam 52 scans the photosensitive drum 51 while the latter is being rotated in the direction of arrow a. But, actually the laser beam 52 scanned in the direction of arrow b becomes a laser beam 53 whose locus is slanted by a certain angle relative to the laser beam 52. Therefore, there arises a problem that a correct latent image cannot be formed on the photosensitive drum 51.